Method for recovering petroleum products or the like from subterranean mineral deposits

ABSTRACT

A method for in situ mining, retorting and mineral recovery of hydrocarbon bearing deposits, such as oil shale, wherein a plurality of vertical kilns are formed between two horizontal vertically spaced access shafts using a vertical shaft forming apparatus including an in situ crushing apparatus to obtain a bed of crushed minerals having a relatively uniform particle size distribution in each kiln shaft, substantially all of the particles being retorted in situ to recover the hydrocarbon and the minerals recovered by leaching.

ilnited States Patent [191 Crumb [4 Oct. 16, 1973 [75] Inventor: Robert E. Crumb, Blackwell, Okla.

[73] Assignee: Continental Oil Company, Ponca City, Okla.

[22] Filed: Aug. 2, 1971 [21] Appl. No.: 168,250

[52] US. Cl. 299/2, 166/259 [51] Int. Cl. E21c 41/10 [58] Field of Search 299/2, 4, 5; 166/259 [56] References Cited UNITED STATES PATENTS 2,481,051 9/1949 Uren 299/2 3,502,372 3/1970 Prats 299/5 3,586,377 6/1971 Ellington 299/2 3,460,867 8/1969 Cameron et al. 299/2 3,001,776 9/1961 Van Poollen 299/2 Primary ExaminerErnest R. Purser Attorney-.loseph C. Kotarski et al.

57 'ABSTRACT A method for in situ mining, retorting and mineral recovery of hydrocarbon bearing deposits, such as oil shale, wherein a plurality of vertical kilns are formed between two horizontal vertically spaced access shafts using a vertical shaft forming apparatus including an in situ crushing apparatus to obtain a bed of crushed minerals having a relatively uniform particle size distribution in each kiln shaft, substantially all of the particles being retorted in situ to recover the hydrocarbon and the minerals recovered by leaching.

19 Claims, 5 Drawing Figures s mat METHOD FOR RECOVERING PETROLEUM PRODUCTS OR THE LIKE FROM SUBTERRANEAN MINERAL DEPOSITS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to improvements in methods for recovering petroleum products and associated minerals and, more particularly, but not by way of limitation, to a method for recovering petroleum products and associated minerals from subterranean mineral deposits.

2. Description of the Prior Art There have been various procedures advanced in the past for recovering oil from underground or subterranean formations having a high degree of permeability or, more particularly, from shale deposits. One method developed, in the past, involves the use of in situ combustion wherein a bore hole is initially drilled through the shale deposit and a cavity is then formed at the bottom of the bore hole or, more particularly, at the bottom of the shale deposit. The surrounding shale is then rubbleized by using explosives or the like. A wall is drilled through the bottom of the cavity and in situ combustion is initiated, the combustion products and the displaced hydrocarbon vapors being recovered from the well.

The primary problem has been to develop a method which is economical and practical. In an effort toward this end there have been many experiments and proposals involving the use of nuclear explosives to create the in situ caverns suitable for retorting the broken shale in place. Not only do these methods have the present disadvantage of using nuclear type explosives which use presently involves many complications, but there have also been problems encountered in obtaining uniformly small enough rock particles for an economically adequate recovery during retorting.

One other method proposed in the past involved the forming of a serpentine shaped tunnel through the shale deposit and detonating explosives to implode the walls and ceiling of the tunnel, the resulting shale rubble being processed via in situ combustion which was commenced at one end of the tunnel. This particular method is described in detail in the Smith patent, U.S. Pat. No. 3,437,378, which is assigned to the assignee of the present invention. To some extent, the method disclosed in the Smith patent, referred to above, did involve the combination of external retorting and in situ combustion for recovering petroleum from shale deposits.

SUMMARY OF THE INVENTION The present invention contemplates a combination of the techniques relating to vertical shaft forming, modifled block-caving and underground rock crushing in such a manner that the benefits of in situ retorting and the high recoveries of surface retorting are optimally utilized to provide an overall, economically feasible method for recovering the desired products from an underground mineral deposit containing a pay shale such as an oil shale deposit. The method of the present invention generally involves the drilling of a plurality of vertically oriented bore holes, each bore hole extending through a portion of the mineral deposit and being generally positioned where subsequently fon'ned, vertically oriented kiln tunnels or kiln shafts are to be 10- cated. Horizontally oriented upper and lower access tunnels or drifts are then formed, the upper access drift being located generally at the upper boundary and the lower access drift being located generally at the lower boundary of the mineral deposit to be retorted, the minerals or shale mined during the forming of the access drifts being removed to the surface and retorted via conventional surface retorting techniques. A plurality of kiln shafts are then vertically formed through the mineral deposit, each kiln shaft extending generally between the access drifts. Each kiln shaft is formed utilizing vertical shaft forming apparatus which fragments the mined minerals, the fragmented minerals being crushed via in situ crushing apparatus, in one form, to obtain a bed of crushed minerals having a relatively uniform particle size in each kiln shaft. The crushed minerals in each kiln shaft are then retorted via in situ retorting techniques to revover the petroleum products therefrom.

An object of the invention is to provide a more economical method for recovering oil or the like, and associated minerals from mineral formations containing a pay shale.

Another object of the method is to provide a more efficient and economical method for forming vertical kiln shafts for in situ retorting.

One other object of the invention is to provide a method for recovering oil or the like and associated minerals from pay shale formations wherein the.

crushed particle size is controlled for more efficient and economical in situ retorting.

An additional object of the invention is to provide a method for recovering oil or the like and associated minerals from pay shale wherein a vertical kiln shaft is formed for in situ retorting in a faster, more efficient and more economical manner.

Yet another object of the invention is to provide an efficient and economical method for recovering oil or the like and associated minerals from pay shale deposits combining external retorting and-in situ retorting useful in mining shale deposits in areas wherein access to the shale deposit can be gained via a cliff face or in regions wherein access to the shale deposit is gained via a vertical access shaft.

Another object of the invention is to provide a method for recovering oil or the like and associated minerals from pay shale deposits combining external retorting and in situ retorting in a more efficient and economical manner.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings which illustrate the various embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical, sectional view generally through a subterranean strata showing some of the bore holes and a portion of the access drifts formed generally above and below the mineral formation formed in accordance with the method of the present invention.

FIG. 2 is a horizontal, plan view generally through a subterranean strata showing the upper access drift and some of the kiln shafts formed in accordance with one embodiment of the method of the present invention.

FIG. 3 is a horizontal, plan view, similar to FIG. 2, but showing the access drifts and the kiln shafts formed in accordance with one other embodiment of the method of the present invention.

FIG. 4 is a vertical, cross-sectional view showing one partially formed kiln shaft, and diagrammatically showing the technique of forming such kiln shaft in accordance with the method of the present invention.

FIG. 5 is a vertical, cross-sectional view showing one of the kiln shafts vertically disposed between the upper access drift and the lower access drift, and diagrammatically showing the in situ retorting comtemplated by the method of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in general and to FIG. 1 in particular, shown therein is a vertical section of earth structure or strata having a surface and a subterranean mineral deposit or formation 12 located generally below an overburden 14. The mineral deposit 12 is, more particularly, an oil shale or other such thick or steeply dipping hydrocarbon deposit or the like, and has an upper boundary l6 and a lower boundary 18. The method of the present invention provides a technique for recovering petroleum products or the like from the mineral deposit 12 combining the methods of external retorting and in situ retorting, in such a manner that the petroleum products and associated minerals can be recovered in an efficient and economical manner as will be described in detail below.

Initially, a plurality of vertically oriented bore holes are formed through the mineral deposit 12, each bore hole 20 extending vertically downwardly through the mineral deposit 12. The bore holes 20 are horizontally spaced and positioned in a plan view, such that each bore hole 20 is generally centrally located at each position where a kiln shaft is to be subsequently formed for future retorts, a plurality of bore holes 20 being disposed on each side of the upper access drift 22 and the lower access drift 24 and spaced a predetermined distance horizontally therefrom. The bore holes 20 provide an opening through the mineral deposit 12 for 10- cating the kiln shafts and, in some instances, are also utilized for air openings, pilot-guide openings, the injection of retorting fluids, air or water, into the complete kiln shaft during the in situ retorting, and emergency escape routes, as will be described in greater detail below.

An upper access drift 22 is formed generally horizontally through a portion of the mineral deposit 12, the upper access drift 22 defining the upper limit of the interval of the mineral deposit 12 to be mined and, in one form, being vertically disposed generally adjacent the upper boundary 16 of the mineral deposit 12, as shown in FIG. 1. A lower access drift 24 is also formed generally through a portion of the mineral deposit 12, defining the lower limit of the interval of the mineral deposit 12 to be mined and, in one form, being vertically disposed generally adjacent the lower boundary 18 of the of the mineral deposit 12, as shown in FIG. 1. The lower access drift 24 is thus spaced vertically from the upper access drift 22, and the upper access drift 22 and the lower access drift 24 are each formed utilizing conventional drift mining techniques, which are well known in the art.

The mined portion of the mineral deposit 12 obtained from the forming of the bore holes 20 and the forming of the upper and lower access drifts 22 and 24 is removed therefrom via conventional means such as, for example, via a rail car or conveyor, and the fragmented minerals thus removed are then retorted utilizing a relatively small scale, conventional surface retorting technique or apparatus to recover the desired oil or petroleum products therefrom. It should be noted that the surface retorting apparatus might, in one form, incorporate appropriate crushing apparatus to reduce the mined, fragmented minerals to a uniform particle size for retorting, such crushing apparatus being well known in the art.

Utilizing the method of the present invention, the fragmented minerals removed to the surface from the access drifts 22 and 24 for surface retorting constitute a relatively small percentage of the total minerals pro cessed via surface retorting and in situ retorting such as, for example, approximately 20 per cent to 30 per cent. The major portion of the recovery is thus produced via in situ retorting to reduce the mineral handling expense, in a manner to be made more apparent below.

If the mineral deposit 12 is exposed at an outcrop on the side of a hill, the upper access drift 22 and the lower access drift 24 are, in a preferred form, mined through the mineral deposit 12 utilizing a cliff face mining technique. As shown in FIG. 2, it is contemplated that the upper access drift 22 and the lower access drift 24 (not shown in FIG. 2), which is disposed vertically under or below the upper access drift 22, are formed utilizing such a cliff face mining technique. In this form of the invention, a plurality of additional upper and lower access drifts can be formed through the mineral deposit 12, each pair of access drifts being horizontally spaced an adequate distance from the adjacent access drifts to permit the kiln shafts to be formed, the upper access drift 22, and the lower access drift 24 and the additional upper and lower access drifts being spaced throughout the mineral deposit 12 to recover the petroleum products and associated minerals from a substantial portion of the mineral deposit 12, in a manner which will be made more apparent below.

As shown more clearly in FIG. 2, a plurality of the bore holes 20 are located on each side of the access drifts 22 and 24, each of the bore holes 20 being spaced a horizontal distance from the access drifts 22 and 24. More particularly, some of the bore holes 20 are located in a vertical plane extending along one side of the access drifts 22 and 24, and the remaining bore holes 20 are located in a vertical plane extending along the opposite side of the access drifts 22 and 24, each vertical plane being substantially parallel to the acess drifts 22 and 24 and spaced a predetermined distance horizontally therefrom. The bore holes 20 along each side of the access drifts 22 and 24 are also each spaced horizontally along the surface 10, the particular spacing between each of the bore holes 20 or, in other words, the

horizontal spacing therebetween being determined by the size of the vertical kiln shafts to be subsequently formed. In a preferred form, each bore hole 20 will be centrally positioned through one of the kiln shafts to be subsequently formed thereabout, for reasons and in a manner which will be made more apparent below.

In those regions where access to the mineral deposit 12 cannot be gained via a cliff face, as mentioned above, a central access shaft 26 is formed through a portion of the mineral deposit 12 to provide a vertical access route for moving the mining apparatus therethrough. The various upper access drifts 22 and the various lower access drifts 24 are then formed or mined radially outwardly from the central access shaft 26, in a manner as diagrammatically shown in FIG. 3, one end of each upper access drift 22 and one end of each lower access drift 24 intersecting a portion of the central access shaft 26. In some applications, as indicated before, a plurality of additional upper access drifts, a plurality of additional lower access drifts and a plurality of additional central access shafts are formed through the mineral deposit 12, each access drift and each access shaft being spaced to obtain an optimum spacing of the various kiln shafts throughout the mineral deposit 12 for maximum in situ retorting and subsequent mineral recovery and for mining a substantial portion of the mineral deposit 12, as will be made more apparent below.

It should be noted that the mined, fragmented minerals resulting from the forming of the central access shaft 26 are also removed to the surface for surface retorting and subsequent mineral recovery, in a manner similar to that described before with respect to the upper access drift 22 and the lower access drift 24.

After the upper and lower access drifts 22 and 24 have been formed and the bore holes properly positioned thereabout, in a manner as shown in FIG. 2 or FIG. 3, a plurality of horizontally spaced kiln shafts 28 are formed through the mineral deposit 12, each kiln shaft 28 extending generally between the upper access drift 22 and the lower access drift 24 and forming a subterranean cavity for in situ retorting and subsequent mineral recovery. The kiln shafts 28 are disposed along each side of the upper and lower access drifts 22 and 24. The kiln shafts 28 are, more particularly, located in a vertical plane on each side of the upper and the lower drifts 22 and 24, each vertical plane is spaced a predetermined horizontal distance from the upper access drift 22 and the lower access drift 24. In one form and as shown in FIGS. 2 and 3, each kiln shaft 28 has a generally circularly shaped cross section, and is generally aligned with one of the bore holes 20, each of the bore holes 20 being centrally disposed with respect to one of the kiln shafts 28.

In a preferred form as shown in FIGS. 2, 3, and 5, a plurality of lower perpendicular access drifts 30 are initially formed through a portion of the mineral deposit 12, each lower perpendicular access drift 30 extending generally between and intersecting a portion of the lower access drift 24 and a lower portion of one of the kiln shafts 28 to provide an interconnecting access route therebetween. A plurality of upper perpendicular access drifts 32 are also formed through a portion of the mineral deposit 12, each upper perpendicular access drift 32 extending generally between and intersecting a portion of the upper access drift 22 and an upper portion of one of the kiln shafts 28 to provide an interconnecting access route therebetween. The upper and the lower perpendicular access drifts 32 and 30 thus each provide an access route for moving the kiln shaft forming apparatus into position for the mining of one of the kiln shafts 28 and for subsequently removing such apparatus, in a manner and for reasons to be described in greater detail below.

Although the kiln shafts 28 have been described above as being oriented in planes parallel to the upper and the lower access drifts 22 and 24 and spaced a horizontal distance therefrom, some of the kiln shafts being disposed on each side of the access drifts 22 and 24,

each kiln shaft 28, in one form, could be centrally located generally above the upper access drift 22 and the lower access drift 24. In this form, the bore holes 20 would, of course, be oriented above or, more particularly, aligned with the upper and the lower access drifts 22 and 24, each bore hole 20 extending vertially through the mineral deposit 12, intersecting a portion of the upper and the lower access drifts 22 and 24. If the kiln shafts 28 are oriented in this manner, it would be necessary to complete the in situ retorting in a sequence starting with the kiln shaft 28 located at the end of the upper and the lower access drifts 22 and 24 most remote with respect to the initiating or starting points thereof, since each kiln shaft 28 must be partially sealed with respect to the upper and the lower access drifts 22 and 24 prior to initiating the in situ retorting therein. From the foregoing, it will be apparent that the disposition of the kiln shafts 28, as shown in FIG. 2 or FIG. 3, is preferable, since this orientation provides a greater flexibility in the overall mining operation, allowing the mineral disposed in any particular kiln shaft 28 to be retorted without regard to a particular sequencing, the primary consideration being overall efficiency and economy.

In view of the foregoing, it should be particularly noted that, since the lower perpendicular access drifts 30, in fact, form extensions of the lower access drift 24 for interconnecting the lower access drifts 24 to the kiln shafts 28, the term lower access drift will sometimes be used below to designate the complete lower access drift network, including the lower access drifts 24 and the lower perpendicular access drift 30. In a I similar manner, the term upper access drift" will sometimes be used below to designate the complete upper drift network, including the upper access drift 24 and the upper perpendicular access drift 32.

The method of forming or mining each kiln shaft 28 is diagrammatically shown in FIG. 4. It should be particularly noted that, in a preferred form, each kiln shaft 28 is formed vertically upwardly, generally from the lower access drift 24 through the mineral deposit 12 toward the upper access drift 22, thereby utilizing gravity feed to move the mined, fragmented minerals to the lower position of each kiln shaft 28 for forming a bed of fragmented, crushed minerals therein, in a manner which will be made more apparent below.

The kiln shaft forming apparatus is initially moved through one of the lower perpendicular access drifts 30 to a position generally below the adjoining, cooperating bore hole 20, that is the bore hole 20 formed through or intersecting that particular lower perpendicular access drift 30. The kiln shaft forming apparatus is diagrammatically shown in FIG. 4, and as shown therein generally includes a vertical shaft forming apparatus 34 and, in one form as shown in FIG. 4, the kiln shaft forming apparatus also includes an in situ crushing apparatus 36. In one form, the bore hole 20 also provides what may be referred to as a pilot bore hole for guiding the vertical shaft forming equipment 34 as the kiln shaft 28 is being mined vertically, upwardly thereby. The utilization of the bore hole 20 as a pilot or guidelike bore hole maintains the alignment of the vertical shaft forming apparatus 34 during the mining of the kiln shaft 28, thereby maintaining the predetermined array of kiln shafts 28, as shown in FIG. 2 or FIG. 3, for maximum recovery of the mineral deposit 12.

After the vertical shaft forming apparatus 34 has been positioned for utilization in forming one of the kiln shafts 28, as described above, the kiln shaft 28 is mined or formed in an upwardly direction generally from the lower access drift 24 toward the upper access drift 22 by the vertical shaft forming apparatus 34. As the vertical shaft forming apparatus 34 is moved upwardly through the mineral deposit 12, the vertical shaft forming apparatus 34 fragments the mined minerals. The fragmented minerals or shale, sometimes referred to as rubbleized shale, mined from the formation mineral deposit 12 during the forming of each kiln shaft 28, falls from the roof of the kiln shaft 28 and is retained therein for retorting.

The vertical shaft forming apparatus 34, in a preferred form, is constructed and operated to cooperate with the in situ type of crushing apparatus 36, in one form of the invention, such that the fragmented minerals are guided by chute 49 into and through the in situ crushing apparatus 36. The in situ crushing apparatus 36 is utilized, in a preferred form, if the local rock properties are such that the mined rock breaks off the roof of the vertical kiln shaft 28 in pieces that would be too large for efficient in situ retorting and subsequent mineral recovery. The in situ crushing apparatus 36 may therefore be deleted in those applications where the vertical shaft forming apparatus 34 breaks the mined rock to a size suitable for efficient retorting and subsequent mineral recovery. The in situ crushing apparatus 36, when used, crushes the fragmented minerals to a relatively uniform size, and the crushed minerals are discharged therefrom generally onto the floor or bottom portion of the kiln shaft 28. The crushed minerals, designated in FIG. 4 by the general reference numeral 38, are thus initially deposited on the bottom of the kiln shaft 28, and form a bed for supporting the vertical shaft forming apparatus 34 and the in situ crushing apparatus 36 during the mining of the kiln shafts 28. The depth of the crushed minerals 38 is, of course, increasing as the vertical shaft forming apparatus 34 mines upwardlyvthrough the mineral deposit 12, the crushed minerals 38 thus providing a supporting bed which is moved upwardly following the upward formation of the kiln shaft 28 to maintain the vertical shaft forming apparatus 34 and the in situ crushing apparatus 36 positioned generally near the roof or upper portion of the kiln shaft 28 being formed. Apparatus which operates in a manner similar to that described above with respect to the vertical shaft forming apparatus 34 and the in situ crushing apparatus 36 is well known in the art and a detailed description of the particular construction and operation thereof .is not required herein.

The crushed minerals 38 are preferablecrushed to a uniform size of, for example, one-half inch; however, a 6-inch size may be acceptable in some applications. The exact particle size is controlled via the in situ crushing apparatus 36, and the particular particle size will be somewhat dependent upon the particular in situ retorting process to be utilized.

In one form and as shown in FIG. 4, a vertical removal shaft 40 is constructed in a central portion of each kiln shaft 28 as the kiln shaft 28 is being mined, the removal shaft 40 extending through the bottom or floor portion of the kiln shaft 28. The removal shaft 40 is positioned and sized for the removal of fines and excess minerals, i.e., shale, accumulated during the formation of the kiln shaft 28.

Since the crushed minerals 38 have all been processed through the in situ crushing apparatus 36 during the formation of the kiln shaft 28, the completed kiln shaft 28 or vertical retort, as shown in FIG. 5, thus contains a bed of crushed minerals 38 which are packed in place, having a relatively uniform size and thus having a controlled permeability. After the kiln shaft 28 has been thus completed or mined, the kiln shaft forming apparatus, that is the vertical shaft forming apparatus 34 and the in situ crushing apparatus 36, if required, are then removed via the upper perpendicular access drift 32 and the upper access drift 22 to a position for subsequent utilization in mining other kiln shafts 28.

The top and the bottom of the vertical retort or kiln shaft 28 are sealed prior to initiating the in situ retorting of the crushed minerals 38. More particularly, a portion of the upper perpendicular access drift 32 is sealed via suitable sealing means, indicated generally in FIG. 5 by the reference numeral 42, which may be, for example, a concrete formed wall. A retort withdrawal system 44 is located at the bottom of the kiln shaft 28 for removing the air and petroleum products from the kiln shaft 28 during the in situ retorting, the removal system including a removal pipe 46 having a seal means 48 disposed therein. The petroleum products obtained via the in situ retorting in each kiln shaft 28 are thus generally removed via a portion of the lower access drift 24. The minerals remaining in the spent shale ash, such as,'for example, aluminum and sodium, are then recovered via conventional leaching methods after retorting is completed in each kiln shaft 28. The leaching fluids would be injected either downwardly through pilot bore hole 20 and removed through the retort withdrawal system 44 or, in some applications, it may be desirable to leach the minerals in the reverse direction, injecting the leaching fluids through the retort withdrawal system 44 which would be modified for that purpose, and withdrawing leached products through the pilot bore hole 20 or, in other applications, through the upper access drift 22, which, if utilized, would be modified for that purpose.

in one form, as shown in FIG. 5, a centrally disposed instrumentation shaft 50 can be located in each kiln shaft 28. The instrumentation shaft 50 is, more particularly, a portion of the removal shaft 40 which was constructed during the mining of the kiln shaft 28, as described before. The instrumentation shaft 50 is disposed to support various control devices which may be utilized during the in situ retorting of the crushed minerals 38 and subsequent mineral recovery from the spent shale ash. For example, the instrumentation shaft 50 could include a plurality of temperature and pressure observation holes for monitoring the retort temperature and pressure during the in situ retorting process.

The precise retorting process utilized may, of of course, vary depending upon various circumstances. However, basically combustion is initiated in the kiln shaft 28 and the retorting fluid, air or oxygen is injected into the kiln shaft 28 and continuously circulated therein. As combustion occurs within the kiln shaft 28 or, more particularly, within the layer of crushed minerals 38, the hot combustion gases thus produced cause vaporization of the hydrocarbons contained in the pay shale or crushed minerals 38. The vaporized hydrocarbon products are removed from the kiln shaft 28, as mentioned before, and are condensed and fractionated into the desired products. When the kiln shaft 28 is burned out, the remaining minerals in the ash would be recovered by conventional minerals leaching, in a manner well known in the art.

It should be particularly noted that the flame front advanced through the kiln shaft 28 during the in situ retorting could be started generally at the top in the kiln shaft 28 and advanced toward the bottom thereof or, in some instances, could be started generally at the bottom of the kiln shaft 28 and advanced toward the top thereof. The preferred method would be the former, since if the flame front is initiated at the bottom of the kiln shaft 28, the combustion products would be dropped back through the flame as it advances toward the top of the kiln shaft 28.

The method of the present invention thus provides an economically feasible approach to the problem of recovering petroleum products and associated minerals from subterranean mineral deposits, which combines the processes of surface retorting, in situ retorting, and subsequent mineral recovery. The use of the upper access drifts 22 and the lower access drifts 24, and the orientation of the vertically disposed kiln shafts 28 positioned relative thereto provide a tunneling network for utilizing in situ retorting in a unique manner such that the retorting process and the production therefrom and subsequent mineral recovery can be efficiently controlled in a relatively easy manner. The kiln shafts 28 are each formed in a unique manner such that maximum utilization of gravity feed of the fragmented minerals is obtained, and such that in situ crushing equipment, if required, can be utilized to obtain a controlled permeability and a uniform particle size, thereby facilitating the retorting process. It should be particularly noted again that the method of the present invention, as described above, is particularly desirable for recovering hydrocarbon or petroleum products and associated minerals from pay shale deposits or other thick or steeply dipping hydrocarbon deposits.

Changes may be made in the apparatus or in the various steps of the method described herein without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

l. A method for recovering petroleum products or the like and associated minerals from subterranean mineral deposits, comprising forming a kiln shaft in a generally vertically upwardly direction through a portion of the mineral deposit using a vertical shaft forming apparatus, the fragmented minerals mined from the mineral deposit during the forming of each kiln shaft being retained therein, said kiln forming apparatus and crushing said minerals with said crushing apparatus including an in situ crushing apparatus; and retorting the fragmented minerals retained in each kiln shaft via in situ retorting to recover the petroleum products therefrom.

2. The method of claim 1 wherein the step of forming a kiln shaft is defined further to include:

mining the kiln shaft upwardly utilizing vertical shaft forming apparatus, the vertical shaft forming apparatus fragmenting the mined minerals during the mining of the kiln shaft.

3. The method of claim 2 wherein the step of forming a kiln shaft is defined further to include:

depositing the crushed minerals on the floor of the kiln shaft being formed, the crushed minerals forming a bed for supporting the vertical shaft forming apparatus during the forming of the kiln shaft.

4. The method of claim 2 wherein the step of forming a kiln shaft is defined further to include:

crushing the fragmented minerals from the vertical shaft forming apparatus utilizing in situ crushing apparatus to crush the fragmented minerals to a relatively uniform particle size.

5. The method of claim 1 defined further to include the step of:

leaching the shale ash retained in the kiln shaft to recover the minerals remaining therein.

6. A method for recovering petroleum products or the like and associated minerals from subterranean mineral deposits, comprising: forming an upper access drift generally horizontally through a portion of the mineral deposit; forming a lower access drift generally horizontally through a portion of the mineral deposit, the lower access drift being spaced vertically from the upper access drift; forming a plurality of horizontally spaced kiln shafts using a vertical shaft forming apparatus which includes an in situ crushing apparatus, each kiln shaft extending through a portion of the mineral deposit, generally between the upper access drift and the lower access drift, the fragmented minerals mined from the mineral deposit during the forming of each kiln shaft being retained therein and being crushed by said crushing apparatus: and retorting the fragmented minerals retained in each kiln shaft via in situ retorting to recover the petroleum products therefrom.

7. The method of claim 6 defined further to include:

removing to the surface the mined portion of the mineral deposit from forming of the upper access drift and the lower access drift; and

retorting the portion of the mineral deposit removed to the surface via surface retorting means to recover the petroleum products therefrom.

8. The method of claim 6 defined further to include:

forming a central access shaft generally vertically through a portion of the mineral deposit to provide a vertical access route for moving mining apparatus therethrough; and

wherein the upper access drift and the lower access drift each extend generally radially from a portion of the central access shaft, one end of the upper access drift and one end of the lower access drift intersecting a portion of the central access shaft.

9. The method of claim 6 defined further to include:

forming a plurality of vertically extending, horizontally spaced bore holes through a portion of the mineral deposit, each bore hole being centrally positioned through one of the kiln shafts for ventilation, retorting fluid injection, an emergency escape route and a pilot guide.

10. The method of claim 4 defined further to include:

forming a plurality of additional upper access drifts generally horizontally through a portion of the mineral deposit;

forming a plurality of additional lower access drifts generally horizontally through a portion of the mineral deposit, each additional lower access drift being spaced vertically from one of the additional upper access drifts;

forming a plurality of vertically spaced additonal kiln shafts, each additional kiln shaft extending through a portion of the mineral deposit generally between one of the additional upper access drifts and the additional lower access drift space vertically therefrom, the upper access drifts, the lower access drifts, the kiln shafts, the additional upper access drifts, the additional lower access drifts, and the additional kiln shafts each spaced throughout the mineral deposit to recover the petroleum products and associated minerals from a substantial portion of the mineral deposit.

11. The method of claim 6 wherein each kiln shaft is spaced horizontally a predetermined distance from the upper access drift and the lower access drift,

12. The method of claim 11 defined further to include:

forming a plurality of upper perpendicular access drifts, each upper perpendicular access drift intersecting a portion of the upper access drift and an upper portion of one of the kiln shafts to provide an interconnecting access route therebetween; and forming a plurality of lower perpendicular access drifts, each lower perpendicular access drift intersecting a portion of the lower access drift and a lower portion of one of the kiln shafts to provide an interconnecting access route therebetween.

13. The method of claim 12 wherein the step of forming the kiln shafts includes the forming of horizontally spaced kiln shafts along each side of the upper access drift and the lower access drift.

14. The method of claim 6 wherein the step of forming the vertical kiln shafts is defined further to include:

mining each kiln shaft vertically upwardly utilizing vertical shaft forming apparatus, the vertical shaft forming apparatus fragmenting the mined minerals during the mining of each kiln shaft.

15. The method of claim 14 wherein the step of forming the kiln shafts is defined further to include:

depositing the crushed minerals on the floor of the kiln shaft being formed, the curshed minerals forming a bed for supporting the vertical shaft forming apparatus during the forming of each kiln shaft. 16. The method of claim 15 wherein the step of forming the kiln shafts is defined further to include:

crushing the fragmented minerals from the vertical shaft forming apparatus utilizing in situ crushing apparatus to crush the fragmented minerals to a relatively uniform particle size. 17. The method of claim 15 wherein the step of forming the kiln shafts is defined further to include:

moving the kiln shaft forming apparatus into a position to initiate the forming of each kiln shaft via the lower access drift; and removing the kiln shaft forming apparatus from each formed kiln shaft via the upper access drift. 18. The method of claim 15 define further to include: sealing a portion of the upper access drift generally adjacent the upper portion of each completed kiln shaft; and wherein the step of in situ retorting of the fragmented minerals is defined further to include: injecting retorting fluids into each kiln shaft via the bore hole centrally disposed therein; and removing the petroleum products or the like and associated minerals from the kiln shaft via the lower access drift. 19. The method of claim 6 defined further to include: removing the minerals remaining in each kiln shaft after retorting via conventional leaching tech niques.

* t i i 

1. A method for recovering petroleum products or the like and associated minerals from subterranean mineral deposits, comprising forming a kiln shaft in a generally vertically upwardly direction through a portion of the mineral deposit using a vertical shaft forming apparatus, the fragmented minerals mined from the mineral deposit during the forming of each kiln shaft being retained therein, said kiln forming apparatus and crushing said minerals with said crushing apparatus including an in situ crushing apparatus; and retorting the fragmented minerals retained in each kiln shaft via in situ retorting to recover the petroleum products therefrom.
 2. The method of claim 1 wherein the step of forming a kiln shaft is defined further to include: mining the kiln shaft upwardly utilizing vertical shaft forming apparatus, the vertical shaft forming apparatus fragmenting the mined minerals during the mining of the kiln shaft.
 3. The method of claim 2 wherein the step of forming a kiln shaft is defined further to include: depositing the crushed minerals on the floor of the kiln shaft being formed, the crushed minerals forming a bed for supporting the vertical shaft forming apparatus during the forming of the kiln shaft.
 4. The method of claim 2 wherein the step of forming a kiln shaft is defined further to include: crushing the fragmented minerals from the vertical shaft forming apparatus utilizing in situ crushing apparatus to crush the fragmented minerals to a relatively uniform particle size.
 5. The method of claim 1 defined further to include the step of: leaching the shale ash retained in the kiln shaft to recover the minerals remaining therein.
 6. A method for recovering petroleum products or the like and associated minerals from subterranean mineral deposits, comprising: forming an upper access drift generally horizontally through a portion of the mineral deposit; forming a lower access drift generally horizontally through a portion of the mineral deposit, the lower access drift being spaced vertically from the upper access drift; forming a plurality of horizontally spaced kiln shafts using a vertical shaft forming apparatus which includes an in situ crushing apparatus, each kiln shaft extending through a portion of the mineral deposit, generally between the upper access drift and the lower access drift, the fragmented minerals mined from the mineral deposit during the forming of each kiln shaft being retained therein and being crushed by said crushing apparatus; and retorting the fragmented minerals retained in each kiln shaft via in situ retorting to recover the petroleum products therefrom.
 7. The method of claim 6 defined further to include: removing to the surface the mined portion of the mineral deposit from forming of the upper access drift and the lower access drift; and retorting the portion of the mineral deposit removed to the surface via surface retorting means to recover the petroleum products therefrom.
 8. The method of claim 6 defined further to include: forming a central access shaft generally vertically through a portion of the mineral deposit to provide a vertical access route for moving mining apparatus therethrough; and wherein the upper access drift and the lower access drift each extend generally radially from a portion of the central access shaft, one end of the upper access drift and one end of the lower access drift intersecting a portion of the central access shaft.
 9. The method of claim 6 defined further to include: forming a plurality of vertically extending, horizontally spaced bore holes through a portion of the mineral deposit, each bore hole being centrally positioned through one of the kiln shafts for ventilation, retorting fluid injection, an emergency escape route and a pilot guide.
 10. The method of claim 4 defined further to include: forming a plurality of additional upper access drifts generally horizontally through a portion of the mineral deposit; forming a plurality of additional lower access drifts generally horizontally through a portion of the mineral deposit, each additional lower access drift being spaced vertically from one of the additional upper access drifts; forming a plurality of vertically spaced additonal kiln shafts, each additional kiln shaft extending through a portion of the mineral deposit generally between one of the additional upper access drifts and the additional lower access drift spaced vertically therefrom, the upper access drifts, the lower access drifts, the kiln shafts, the additional upper access drifts, the additional lower access drifts, and the additional kiln shafts each spaced throughout the mineral deposit to recover the petroleum products and associated minerals from a substantial portion of the mineral deposit.
 11. The method of claim 6 wherein each kiln shaft is spaced horizontally a predetermined distance from the upper access drift and the lower accEss drift.
 12. The method of claim 11 defined further to include: forming a plurality of upper perpendicular access drifts, each upper perpendicular access drift intersecting a portion of the upper access drift and an upper portion of one of the kiln shafts to provide an interconnecting access route therebetween; and forming a plurality of lower perpendicular access drifts, each lower perpendicular access drift intersecting a portion of the lower access drift and a lower portion of one of the kiln shafts to provide an interconnecting access route therebetween.
 13. The method of claim 12 wherein the step of forming the kiln shafts includes the forming of horizontally spaced kiln shafts along each side of the upper access drift and the lower access drift.
 14. The method of claim 6 wherein the step of forming the vertical kiln shafts is defined further to include: mining each kiln shaft vertically upwardly utilizing vertical shaft forming apparatus, the vertical shaft forming apparatus fragmenting the mined minerals during the mining of each kiln shaft.
 15. The method of claim 14 wherein the step of forming the kiln shafts is defined further to include: depositing the crushed minerals on the floor of the kiln shaft being formed, the crushed minerals forming a bed for supporting the vertical shaft forming apparatus during the forming of each kiln shaft.
 16. The method of claim 15 wherein the step of forming the kiln shafts is defined further to include: crushing the fragmented minerals from the vertical shaft forming apparatus utilizing in situ crushing apparatus to crush the fragmented minerals to a relatively uniform particle size.
 17. The method of claim 15 wherein the step of forming the kiln shafts is defined further to include: moving the kiln shaft forming apparatus into a position to initiate the forming of each kiln shaft via the lower access drift; and removing the kiln shaft forming apparatus from each formed kiln shaft via the upper access drift.
 18. The method of claim 15 defined further to include: sealing a portion of the upper access drift generally adjacent the upper portion of each completed kiln shaft; and wherein the step of in situ retorting of the fragmented minerals is defined further to include: injecting retorting fluids into each kiln shaft via the bore hole centrally disposed therein; and removing the petroleum products or the like and associated minerals from the kiln shaft via the lower access drift.
 19. The method of claim 6 defined further to include: removing the minerals remaining in each kiln shaft after retorting via conventional leaching techniques. 